SECONDARY REFRIGERANTS: MAINTAINING CONDITION AND PERFORMANCE

Transcription

1 SECONDARY REFRIGERANTS: MAINTAINING CONDITION AND PERFORMANCE The Ontario Recreation Facilities Association Inc (ORFA) regularly researches and writes about issues that could affect our members These documents provide an opinion on key risk management issues but are not meant to provide any form of legal opinion or official interpretation No one should act on such information without appropriate professional advice after a thorough examination of the particular situation All rights reserved 2013 Ontario Recreation Facilities Association Inc October 2013 Introduction Maintaining all liquid levels in the refrigeration plant room is an important part of the inspection and upkeep of the system Proper liquid levels help to ensure optimum performance thus reducing equipment wear and energy consumption The most common cycle in an ice rink uses two (2) refrigerants: 1 Primary 2 Secondary The most common primary refrigerants found in North America are ammonia and Freon Both are installed in the refrigeration system as a liquid and will go through a change of state (liquid to gas and back to liquid) during the refrigeration cycle The primary refrigerant will not lose any of its stability; it remains constant regardless of use or age The refrigeration technician must maintain the manufacturer s recommended level to ensure optimum performance of the secondary refrigerant Member Tips: Freon "We change our filter dryers every year and have found this to be a key preventative maintenance function in older plants If we have problems with shaft seals we will take Freon sample for analysis" Ammonia We are currently experimenting with our refrigeration contractor with a new ammonia filter dryer system We will continue to keep the ORFA in tune with the results of this project Secondary refrigerants generally consist of antifreeze solutions, corrosion inhibitors and at times biocides Secondary refrigerants are available in two (2) categories aqueous (water based) and non aqueous solutions Aqueous secondary refrigerant solutions are most often mixtures of compounds such as calcium chloride or ethylene glycol and water An example of a non aqueous solution would be carbon dioxide Our discussions will focus on aqueous secondary refrigerants only For an example of a non aqueous solution see enewsletters/f Pearson featurepdf Aqueous secondary refrigerants are installed as a liquid and do not change state Brine as a secondary refrigerant may lose some of its stability through use, age or contamination while glycol secondary refrigerants are considered to have a higher state of stability yet contamination is still a great concern Both the primary and secondary refrigerants are held within sealed systems and when properly maintained loss from either of these elements should not occur Any loss or fluctuation should be closely monitored, recorded and acted upon Choosing a Secondary Refrigerant Secondary refrigerants are also referred to as heat transfer fluids This fluid is cooled by the primary refrigerant then cycled through a series of pipes to the cooling load location (ice) and back to the refrigeration system to repeat the cycle In an indirect system, the process includes a heat exchanger (chiller), a condenser, compressor and pump All of these parts will have some resistance therefore it is important that the selected secondary Ontario Recreation Facilities Association Inc T F

2 refrigerant provide a cost effective and energy efficient application Secondary refrigerants will be required to meet some basic requirements (not all identified): Positive thermal conductivity High specific heat Low viscosity Quality chemical corrosion inhibitor Stability with no separation or degrading Non toxic Non Flammable Freezing point is best described as the crystal formation when a liquid turns from a fluid into a solid state The common practice is to choose a secondary refrigerant with a freezing point of no less than 5 10 C below the system s normal operating temperature Viscosity of a fluid describes the state of being thick, sticky, and semifluid in consistency thus raising the internal friction of the system as it goes about cycling Viscosity plays a key role in piping size and pump selection during the construction phase Proper selection will help to ensure a cost effective day to day operation Density is the concentration level of the secondary refrigerant fluid Checking density is the most effective way of determining secondary refrigerant condition The majority of aqueous secondary refrigerants found in ice rinks are salt based and are corrosive by nature To reduce system corrosion it is imperative to select and maintain a quality corrosion inhibitor or chemical stabilizer Equipment Inspections Ongoing equipment inspection is the responsibility of the owner as set out in the Operating Engineer Regulation Persons permitted entry into a refrigeration plant room in order to perform work must be competent as set out in the Ontario Occupational Health and Safety Act to do so Inspection of secondary refrigerant levels will help to quickly identify operational issues of the plant Slight fluctuation of secondary refrigerant levels should be considered normal However, ongoing reduction in level or dramatic fluctuations may be an indication of a system leak and should be recorded in the registered plant room log book, investigated and repaired Regular off season inspection of the plant room is also an important part of maintaining the system During the shutdown period it is important to continue to monitor the condition of the plant It is not uncommon for the secondary refrigerant pump to be turned on for a day each month of shutdown to circulate the fluid to ensure seals in the system remain lubricated Inspecting the plant room weekly during shutdown is strongly recommended Member Tip: "Our solution was to install a float in the expansion tank that is tied into a BAS system to monitor the fluid level of the secondary refrigerant loop The BAS system can be set up to allow for level fluctuation on startup and shut down of the pump, send an alarm and even shut down the plant or pump for a specific rink in a multi pad facility" Air in the System Another enemy to the system is the introduction of air Air contains moisture which will contribute to internal deterioration of the system; it may also reduce the effectiveness through blockage of the refrigeration cycle Air must be removed from the system Refrigerant Leaks in the Plant Room Aqueous secondary refrigerants are water based and therefore present a worker slip hazard if they escape from the system and on to the plant room floor Use of proper PPE as outlined in the Material Safety Data Sheet is Ontario Recreation Facilities Association Inc T F

3 also considered essential worker protection when dealing with leaks System Maintenance Plant owners should design and maintain a comprehensive refrigeration maintenance program specific to each registered refrigeration plant room A contractual working relationship with an accredited refrigeration contractor is a legal obligation under the Operator Engineer Regulation (OER) This contractual obligation does not lessen the responsibility of the owner to maintain a safe registered refrigeration plant room For a maintenance plan to be effective the owner must have a qualified internal representative (responsible person) that understands the legislative obligations that must be met, the on site refrigeration equipment and what investment must be made to keep the registered plant room safe and serviceable Although there may be some human risks associated with secondary refrigerants use and contact they should be viewed as being manageable Maintaining concentration levels as well as corrosion protection will help ensure maximum energy efficiency and equipment lifecycle Maintaining fluid density ensures maximum operational capability while reducing the chance of a system freeze up Secondary refrigerants must have the density checked no less than once per year This test can most likely be performed by the refrigeration contractor but there should be no assumption that it will be conducted without direction from the owner When topping up any secondary refrigerant it is important to note that not all inhibitors can be mixed with hard water It must also be noted that propylene and ethylene glycol refrigerants are susceptible to bacterial contamination; a biocide must be added and properly maintained in these types of systems Corrosion problems can escalate within a short period of time (months vs years) The lack of inhibitor use will result in excessive corrosion and premature equipment failure An additional inspection of the inhibitor must also be planned Determining how often this test must be performed (1 3 times per year) will be based on the age, ongoing maintenance program and an evaluation of the system Simple evaluation of plant room condition can be performed by viewing control valves Valves that are corroded are indicators of poor maintenance Refrigeration equipment can be maintained through low cost methods Regularly turning valves to ensure smooth operation, cleaning away dirt and rust and painting as required will all serve to prolong function and life of the equipment Member Tip: We used to do secondary refrigerant testing annually on our calcium chloride systems but from past experiences and with equipment failure we now do our testing semiannually With this change we still have to make adjustments to the secondary refrigerant each time we test This indicates that the breakdown of refrigerant can happen quite quickly Mechanics Tips: When sampling brine, a steady clean stream or sample should be taken Sampling streams should be flushed enough to get a representative sample from the system and not the entrapped line which does not represent the system Sample bottle must be clean and dry or it is new Side stream filtration is recommended to trap sediment, dirt and debris However, this may interfere with dosing of certain additives and may depleted their charge along with the brine system's debris Filtration before dosing may be preferred If the CaCl brine system is maintained Ontario Recreation Facilities Association Inc T F

4 well without any ups and down, organic inhibitors tend to stabilize Adding a new organic inhibitor charge to a brine system for the first time or when the system is new may see the inhibitor "consumed" as it makes it's protective layers within the system Chemists suggest that organic inhibitors will deplete until a stage comes when it is stabilizes Consumption of inhibitor in a stabilized system is not supposed to be as aggressive When the system has ups and down like sudden change in the system, ph up or down, adding any additional chemical into the system etc may also consume the inhibitor It is always hard to predict what any new additive may do to organic inhibitors Conclusion The condition and performance of secondary refrigerants is necessary for quality refrigeration plant operations Plant operators must be able to identify the type of secondary refrigerant used and all of its elements This is best accomplished by maintaining up to date Material Safety Data Sheets (MSDS) It is essential to keep on site records that state operational levels, concentration and fluid quality reports Training staff to inspect equipment and to safely take appropriate action for minor problems will help to prevent the potential of major problems Further, staff must be trained to deal with spills and leaks in a safe and environmentally friendly manner Creating and maintaining a comprehensive program for secondary refrigerant inspection is the most essential element of preserving its overall condition and performance Disclaimer Ontario Recreation Facilities Association Inc, 2013 The information contained in this reference material is distributed as a guide only; it is generally current to the best of our knowledge as to the revision date, having been compiled from sources believed to be reliable and to represent the best current opinion on the subject No warranty, guarantee or representation is made by ORFA as to the absolute correctness or sufficiency of any representation contained in this reference material and ORFA assumes no responsibility in connection therewith; nor can it be assumed that all acceptable safety and health measures are contained in this reference material, or that other or additional measures may not be required in particular or exceptional conditions or circumstances While ORFA does not undertake to provide a revision service or guarantee accuracy, we shall be pleased to respond to your individual requests for information at any time Reference to companies and products are not intended by the publisher as an endorsement of any kind ORFA EDITORIAL NOTE: Member/Contractor Tips are provided for information only Members should always research and investigate all options that meet their currents needs as part of an internal review process Ontario Recreation Facilities Association Inc T F

5 Appendix Brine Analysis Report Calcium Chloride Table DOWFLAKE Xtra 83 87% Calcium Chloride product information sheet Ontario Recreation Facilities Association Inc T F

6 CIMCO BRINE ANALYSIS REPORT Brinemastercimcodoc Rev Date Feb 19/03 Rev # 0 PO#: SHIPPER NO:663 DATE PROCESSED: 05/29/07 LABORATORY NO: 07164E DATE RECEIVED: 04/27/07 RECEIVED FROM: Toronto BRINE TYPE: Calcium Chloride FACILITY:004 Rink #4 DESCRIPTION ACTUAL PREVIOUS TYPICAL Colour/Clarity: Light green after Clear/Yellow Chromate filtration Clear/Blue (575) Ammonia Check Test: Nil Nil Odour: Nil Nil Supernatant: Nil Nil Sediment: 4 lb/1000 gal Nil ph: (Chromate) (575) Specific Gravity at 60 F: Percent Calcium Chloride: 209 % % Freeze Point: 31 F 10 deg F Inhibitor Concentration: Nil 1600 ppm (Chromate) 27 ppm 100 ppm (575) PH adjust: Add 100 milliliters of 50 % Sodium Hydroxide solution per 1000 US Gal of brine Freeze point adjust:add 71x50 lb of 77 % Calcium Chloride flakes or 61x50 lb of 90 % Calcium Chloride pellets per 1000 Gal of brine Inhibitor adjust: Add 20 L of Ancobrand inhibitor 575 per 1000 Gal of brine Filtration adjust: Recommended filtration COMMENTS: Please follow the sequence as 1 Add Sodium Hydroxide and let it dissolve completely, 2 Filter, 3 Add the rest Thanks; any questions, please don t hesitate to call us ed to: John McAllister, Tony Roehrig Chief Chemist: Sat Anand Date: 05/29/07 Cimco makes no warranties or representations whatsoever, either express or implied, oral or written, in fact or by operation of law or otherwise, regarding any measurements and recommendations and disclaims all liability in connection with or arising as a result of providing any services, measurements and recommendations Cimco accepts no liability or responsibility for any service, measurement or recommendation and does not and shall not be deemed to approve the design, use or function of, any item, material, article or product in connection with the services, measurements or recommendations provided

7 CALCIUM CHLORIDE TABLE Specific Gravity at 64 Degrees F Degree Beaume at 64 Degrees F Degree Salometer at 64 Degrees F Per Cent Of CaC1 2 Freezing Point in Degrees F Ammonia Gauge Pressure Pounds per Square Inch vacuum 5 vacuum 85 vacuum 12 vacuum 15 vacuum 10 vacuum 4 vacuum 15 pounds

8 Product Information DOWFLAKE Xtra 8387% Calcium Chloride Unique Properties for Xtra Advantage Application DOWFLAKE Xtra 8387% Calcium Chloride possesses distinctive properties that make it the ideal choice for ice melting, dust control, concrete acceleration and many other applications Its higher concentration provides a lower application rate than conventional 7780% calcium chloride flake DOWFLAKE Xtra releases heat to melt snow and ice faster and across a wider range of temperatures than other materials Mix it with rock salt, sand and gravel to improve their performance It reduces dust on unpaved surfaces by absorbing moisture from its surroundings, keeping the surface damp and binding dust particles to the gravel Adding it to concrete results in reduced time for initial and final set, increased early strength and protection in cold weather When put into solution, DOWFLAKE Xtra is effective in many other applications, including tire weighting and brine refrigeration (See tables on reverse) Description DOWFLAKE Xtra is a purified inorganic salt produced by removing water from a naturally occurring brine solution Unlike other processes used to produce calcium chloride, the brine process does not involve reactions with chemicals such as hydrochloric acid or ammonia The National Organic Standards Board noted this distinction when it classified the brine process as nonsynthetic Properties Characteristic Calcium chloride assay Flake size distribution Larger than 48 mm From 06 to 48 mm Smaller than 06 mm ASTM D98 purity requirements (1) Total alkali chlorides (as NaCl) Total magnesium (as MgCl 2 ) Calcium hydroxide (1) On an active ingredient basis Storage Solid calcium chloride is both hygroscopic and deliquescent This means that the product can absorb moisture from the air, even to the point of converting to liquid brine For this reason, solid calcium chloride should be protected from excessive exposure to moisture to maintain product quality while in storage Store in a dry area Opened packages should be tightly resealed after each use For full safety and handling details, refer to the current Material Safety Data Sheet for this product, available at wwwoxycalciumchloridecom Availability Typical Value >83% <20% >75% <5% <6% >05% >02% DOWFLAKE Xtra is available in various package sizes, and in bulk truck and bulk rail DOWFLAKE Xtra meets or exceeds ASTM D98 and AASHTO M144 requirements for calcium chloride purity ASTM classification for DOWFLAKE Xtra is Type S, Grade 1, Class A Trademark of The Dow Chemical Company

9 Making Calcium Chloride Solutions From DOWFLAKE Xtra Calcium chloride releases heat when it is dissolved Make sure that the dissolving vessel is appropriately constructed for handling hot solutions Fill the vessel with cool water (less than 80ºF/26ºC), then slowly add calcium chloride while continuously stirring Solids kept in motion will dissolve quickly; however, solids that sit motionless on the vessel bottom may form a hard cake that will dissolve more slowly Making 100 Gallons of Solution From DOWFLAKE Xtra Calcium Chloride (1) Making 100 Liters of Solution From DOWFLAKE Xtra Calcium Chloride (1) % CaCl 2 Target % CaCl 2 Target Specific Gravity (77ºF) Specific Gravity (26ºC) ºF (lb/gal) ºC (kg/l) Weight of Product to Dissolve (lb) Weight of Product to Dissolve (kg) Water Volume (gal) Water Volume (L) Expected Temp Rise (ºF) Expected Temp Rise (ºC) Solution Freeze Point (ºF) Solution Freeze Point (ºC) (1) To make up solution volumes different from those used as the basis above (100 gallons or 100 liters), simply adjust the Weight of Product to Dissolve and the Water Volume numbers in the tables by the ratio of the desired solution volume to 100 For example, to make 2000 gallons of 32% solution: Weight of Product to Dissolve = 415 x (2000/100) = 8300 lbs; Water Volume = 82 x (2000/100) = 16 gals For more information or to find an authorized distributor of OxyChem s calcium chloride products, please call or visit our website (888) wwwoxycalciumchloridecom Important: The information presented herein, while not guaranteed, was prepared by technical personnel and is true and accurate to the best of our knowledge NO WARRANTY OF MERCHANTABILITY OR OF FITNESS FOR A PARTICULAR PURPOSE, OR WARRANTY OR GUARANTY OF ANY OTHER KIND, EXPRESS OR IMPLIED, IS MADE REGARDING PERFORMANCE, SAFETY, SUITABILITY, STABILITY OR OTHERWISE This information is not intended to be allinclusive as to the manner and conditions of use, handling, storage, disposal and other factors that may involve other or additional legal, environmental, safety or performance considerations, and OxyChem assumes no liability whatsoever for the use of or reliance upon this information While our technical personnel will be happy to respond to questions, safe handling and use of the product remains the responsibility of the customer No suggestions for use are intended as, and nothing herein shall be construed as, a recommendation to infringe any existing patents or to violate any Federal, State, local or foreign laws Printed in USA Form No P&M